Project Summary This Small Business Innovation Research Phase 1 project will develop a novel magnetic cytometer to rapidly isolate, identify and sort single intact and viable cells from heterogeneous cell population for single cell analysis. Single cell analysis is the key to investigate fundamental biological principles behind cell heterogeneity and disease evolution. Sorting of single cells from heterogeneous population has been essential to life science and clinical research such as monoclonal antibody production and cell line development. Recently there is a strong demand from single cell analysis on rare cells, such as circulating tumor cells (CTCs), circulating fetal cells, stem cells, antigen-specific T- or B-cells, and disseminated tumor cells (DTCs). However, conventional single cell sorting technology has limited capabilities to sort single cells from rare cell population. For instance, micromanipulation and serial dilution are time consuming and low-throughput; fluorescent-activated cell sorting (FACS) suffers from target cell loss and only applies to abundant cell populations. In addition, current technique used for rare cell identification requires cell fixation which causes loss of cell viability and thus prohibits many downstream molecular and functional analysis. Therefore, the development of a high- throughput cytometer for single intact cell sorting will have wide applications in bioscience research as well as potential clinical benefit. The ultimate goal of this research is to develop an easy-to-use high-throughput cell sorter for single cell analysis in basic and clinical research.